The shape of the geosphere
is constantly changing. Erosion of beaches and landscapes occurs on a small
level. Volcanoes can make larger changes all at once. But over millions
of years the greatest change in the geosphere is due to continental drift.
The surface of the Earth and the crust beneath it float
on a sea of molten lava called the mantle. Major cracks in the Earth, called
faults, let some parts of the crust sink down into the mantle while others
rise up out of it. Eventually this causes the continents to glide and shift
their positions. The continents are moving about four inches a year, but
over millions of years this adds up.
Hold still! Continental
Drift Still Frames (166 k)
- Which continents were next to each other in the past?
- When were the continents closest together?
- Was the Atlantic Ocean smaller, larger, or the same 130 million years
- Do you think it will be cold or warm in Antarctica 250 million years
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